Breech operating mechanism for automatic firearms



Jan. 1952 c. E. SIMPSON 2,582,288 BREECH OPERATING MECHANISM FOR AUTOMATIC FIREARMS Original Filed June 7, 1946 2 NETS-SHEET l nneE Sim .sun

Jan. 15, 1952 c. E. SIMPSON 2,582,288

BREECH OPERATING MECHANISM FOR AUTOMATIC FIREARMS Original Filed June 7, 1946 2 SHEETSSHEET 2 I mww grwe/wfoo lllnrend E'E. Simpson.

Patented Jan. 15, 1952 UNITED STATES PATENT OFFICE BREECH OPERATING MECHANISM FOR AUTOMATIC FIREARMS Clarence E. Simpson, Springfield, Mass., assignor to the UnitedStates of America as represented by the Secretary ofWar 'flriginal application June "7, 1946, Serial .No.'

575,124. IDivided and thisapplication February 4, 1948, Seriai.-No.-6,153

(Granted under the act of March 3, 1883, as

'7 Claims.

This invention relates to a breech timing mechanism for automatic firearms. and more particularlyto a device for insuring that the breech block will go into battery position in properly timed relationship with the other breech elemerits of the firearm.

This application is a division of my copending application for Firearm, Serial No. 675,124, filed June-'7, 1946, now matured in Patent No. 2,555,379 dated June 5, 1951.

In the firearm referred to in the above-mentinned copendin application, there is provided a recoiling barrel, barrel extension, breech block, and breach block carrier which are arranged for lnng'itudinal reciprocation .within the receiver.

fllhe breech .bloc'k .isiconstructed to slide along an inclinediplaneon the breech block carrier. When .thezrecoilingzmembers are in the extreme recoiled position, the .recoil spring acts to return the barrel and :barrel extension forwardly and the breech :block and breech block carrier tend to move along with the barrel .and barrel extension. However, the breech block carrier is retained in the recoiled position by a latch. .Thus only the breechhlock can move forwardly with the barrel and barrel extension. However, the breech block is permitted to travel downwardly on the breech :block carrier 2. sufiicient amount to permit'unlocking of such block from the barrel extension and when such occurs the breech block is held on the breech :blockcarrier and the barrel and barrel extension proceed to the battery position.

After the barrel and barrel extension have reached battery position, the breech block is .released from the breech block carrier and then both the block and carrier g forwardly into breeched position. It is most essential that the breech block be not released until the barrel and barrel extension are in battery position as the breech block and carrier could be released at an inopportunemoment andcome forwardly at the wrong time thus introducin the possibility of dam and premature discharge of a live .round in the feedway of the firearm.

.Accordinglyit is an object of this invention to provide a'clevice to insure that the breech block wilhgointo battery position in properly timed .relationship with the other reciprocating breech membersrofthe firearm.

.- The specific .nature ;of the invention as well as amended April 30, 1928; 370 0. 'G. 757') 2 other objects and advantages thereo'f will clearly appea-r'from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. '1 is a fragmentary side view of :a firearm ShOWil'lg the recoiling parts in the battery \position.

Fig. 2 is a view similar to Fig. 1 but showing the recoiling elements in the extreme .recoil'ed position and showing the depressor bar in :its rearmost position and contacting the roller of the depressor.

Fig. '3 is a vi'ew-similarztoF'igs. l and 2 showing the barrel and barrel extension approaching battery position.

Fig. 4 is a viewsimilar to Fig. 3 showing the barrel and barrel extension :in battery position but with the breech block in the fully depressed state and-also showingthe depressor bar urged to its extreme forward position by'the barrel :extension.

.Fig. .5is an enlarged detail side elevational riew showing the breech block fullydepressed by the depressor.

Fig. '6 is an enlarged detail opposite side .elevational view-showing thestop secured tozthe inclinedarmrof the breech block.

In the accompanying drawings there is shown a firearm -embodyin thisinvention. :Such firearm comprises mainly arreceiver H1, a barrel ll, barrel extension 122, :breech block 13, and :a breech block carrier .14. Barrel extension :12 is jpreierablyqthreadedlysecured to barrel 1H and the barrel extension [2 is slidably mounted in receiver 49 for longitudinal reciprocating movement. A feedway member-l5 is pivotally 'mountedon receiver Hi and substantially surrounds barrel lei. Barrel extension 11-2 is shown :inFig. .1. Breech block I3 ,andicarrier Hi:are'slidablymounted in receiver 19 and are arranged for longitudinal reciprocating movement :as will he presently described.

Breech block 13 comprises-a substantially vshapedzmember-having a vertical arm l6 and a rearwardly sloped .arm ii. A T-slot .(not shown) is provided .on the forward vertical face .of arm 15 to receive the head .of a cartridge 45. A plurality of integral locking lugs it are provided on the sides of vertical arm it of breech :block: 3 which engage corresponding lugs in barrel .exten sion 42 when breech block i3 is raised into Lbatteryposition with barrel extension 12. A :breech block stop it .is secured to the inclined arm I? of breech block 13 near the top thereof as by -a screw 20. The stop ll; comprises a substantially ward movement of breech block I3 on carrier I4. An upwardly projecting lug. 5D is provided on the other side of stop l9 and the lower corner of such lug is engaged by a breech block depressor 2| being provided with locking means to be later described.

Breech block carrier |4 comprises a horizontal arm 22 and an integral upwardly inclined arm 23 as shown in Figs. 1 and 4. Breech block I3 is secured to the upwardly inclined arm 23 of breech block carrier M in such a manner that the breech block |3 will slide along such face relative to the carrier.

Breech block depressor 2| is pivotally mounted on breech block carrier |4 as shown in Figs. 1, 2, 3, and 4. Breech block |3 is arranged to be disengaged from breech block carrier M by depressor 2| at the desired time as will be later described. Depressor 2| comprises a body portion 24 having in the center thereof an integral upright arm 25. The extreme upper portion 46 of arm 25 is bent forwardly somewhat as shown in the above-mentioned figures and a notch '26 is provided in the uppermost corner thereof to engage 'stop i9 thereby locking breech block |3 in the battery position.

Depressor 2| is pivotally mounted by a transverse pin 21. Depressor 2| is fixedly secured to pin 27. Such pin is journaled within a suitable transverse hole in the breech block carrier l. The bottom surface of the body portion 24 of depressor 2| rests on the top surface of arm 22 of carrier I4. The forward edge of body portion 24 is rounded as at 28 to permit rotation of depressor 2| about the axis of pin 27. A plunger 29 suitably spring biased is vertically mounted within a downwardly opening hole in the rear edge of body portion 24 to bias arm 25 in a, counterclockwise direction to insure that notch 26 will engage the lower corner of stop l9. A roller 30 is mounted on a fixed stud 3| on the side of body portion 24 as shown in the drawings.

A depressor bar 32 comprises a substantially rectangular bar slidably mounted on the left side of the firearm for reciprocating longitudinal movement. A latch 33 is pivotally mounted between two integral lugs 34 provided near the forward end of depressor bar 32 by a suitable pin which is supported by such lugs. Latch 33 is biased inwardly against barrel extension |2 by a suitable spring (not shown). Ilatch 33 engages a stud 35 provided on the lower right hand corner of barrel extension l2 to carry depressor bar 32 forwardly as will be presently described.

An upwardly sloped cam surface 36 is formed on a vertical lug 3'! provided on the rear end of depressor bar 32. Lug 31 also projects inwardly to engage roller 33 on depressor 2|. An. overhanging shelf 38 is provided on an integral raised lug 39w somewhat ahead of lug 31. Shelf 38 projects over the forward edge of cam surface 33 and is provided to engage roller 33 so that depressor 2| may be disengaged from stop l9, thus permitting breech block l3 to become separated from barrel extension l2. Two longitudinally disposed slots 40 and Al are provided at the rear and forward ends of bar 32, respectively, through each of which is inserted a screw 42 which engages suitable threaded holes in receiver ID. A washer s3 is preferably placed under the 2 head of each screw 42 and screws 42 are so adpermit free longitudinal movement limits of slots 40 justed as to of depressor bar 32 within the and 4|. u v

Depressor bar 32 functions in the following manner: Upon depressing depressor 2|, the breech action, comprising essentially breech block l3 and breech block carrier l4, may be manually retracted rearwardly. A cartridge strip 44 containing cartridges 45 may then be inserted in feedway l5 whereupon the action is permitted to close. Breech block |3 then rises vertically to the closed locked position as shown in Fig. 1 thereby engaging the rim of the first cartridge contained in strip 44 in the T-slot provided in the face of breech block I3. To feed the cartridge now held in the face of breech block l3, depressor 2| is disengaged from stop I!) as previously described so that breech block |3 can drop downwardly sufficiently to disengage lugs l8 from the corresponding lugs in barrel extension |2 thereby unlocking such breech block from barrel extension l2. The action is then withdrawn rearwardly until the rear end of carrier I4 is approximately from the end of its extreme recoil position. However, when the action is approximately 2 from the end of such stroke, roller 32 on depresso 2| engages cam surface 36 on depressor bar 32. Depressor portion 46 contacting stop l9 then starts breech block I3 downwardly on carrier l4. When roller 30 strikes the vertical portion of cam 36, as shown in Fig. 4, depressor 2| has fully depressed breech block l3 so that the cartridge held in such breech block is aligned within the chamber of barrel While the gun is being manually charged, depressor bar 32 is held stationary in the forward position through the connection of such bar to barrel extension |2 by stud 35. Breech block I3 then moves forwardly to chamber the cartridge held in the face thereof, and upon chambering the round the horizontal movement of the breech block is changed to a vertical movement thereby engaging lugs it with corresponding lugs in breech block |3 to lock such breech block securely to barrel extension l2.

When the round is fired, the action, along with the barrel and barrel extension recoil rearwardly and near the end of the recoil stroke roller 32 on depressor 2| passes under shelf 38 on depressor bar 32. This causes depressor 2| to rotate clockwise and become disengaged from stop it on breech block I3. Stud 35 on barrel extension l2 strikes the forward face of lug 39 to carry depressor bar 32 to the rear as shown in Fig. 2. Such bar is forced rearwardly to prevent roller 33 from binding on cam surface 36. Barrel H and barrel extension l2 are started forwardly on the counterrecoil stroke by the recoil spring (not shown). The carrier is retained in the rearmost position as shown in Fig. 4 by a carrier latch (not shown). Forward movement of barrel H and barrel extension it? forces block l3 to slide downwardly on the inclined arm 23 of carrier l4 until the locking lugs hi on block is are aligned with corresponding openings in barrel extension l2 (not shown).

Thus barrel H and barrel extension I2 become unlocked from breech block l3 and are moved into battery position by the bias of the barrel spring (not shown). Breech block I3 is then yieldingly retained in the unlocked position on carrier l4 until stud 35 on barrel extension I2 strikes latch 33 on depressor. bar 32. Such bar is then carried forward by barrel until such barrel comes to a final stop at its forward position as shown in Fig. 4. As the depressor bar 32 moves forwardly, shelf 38 moves off the roller 30 and the cam surface 36 on depressor bar 32 guides roller 30 and partially rotates depressor 2! in a counterclockwise direction as viewed in Fig. 4. This forces breech block l3 down the inclined surface of carrier [4 thereby aligning the live round contained in the breech block with the axis of the bore. Downward travel of the breech block on carrier l4 strikes the carrier latch (not shown) thereby releasing such latch and permitting the breech block to go forwardly to the battery position.

It is therefore apparent to those skilled in the art that there is here provided a mechanism that will positively insure that the breech block of an automatic firearm will go into battery position in timed relationship with the cooperating elements of the breech mechanism.

I claim:

1. In a firearm having a receiver, a barrel extension slidably mounted in said receiver for reciprocating movement, a barrel secured to said barrel extension, a breech block carrier slidably mounted in said receiver for reciprocating movement parallel to said barrel and barrel extension movement, a breech block guide surface on said carrier angularly disposed relative to the path of movement of said carrier and located rearwardly of said barrel extension, a breech block slidably mounted relative to said guide surface for reciprocal movement between two spaced positions on said guide surface, a stop secured to said breech block, a depressor pivotally secured to said carrier constructed and arranged to engage said stop, said depressor being provided to hold said breech block on said carrier in the uppermost of said two spaced positions, and means for disengaging said depressor from said stop.

2. The combination defined in claim 1 wherein said means comprises a bar slidably mounted for limited longitudinal movement on said receiver, a catch on one end of said bar arranged to be enaged by a stud on said barrel extension, and a cam on the other end of said bar being provided to rotate said depressor when said barrel stud engages said catch as said barrel and barrel extension move into battery position whereby said depressor forces said breech block downwardly on said carrier to the lowermost of said two spaced positions.

3. The combination defined in claim 1 wherein said means comprises a stud secured to said barrel extension, a bar slidably mounted for longitudinal movement on said receiver, and an upwardly projecting shelf being provided adjacent the rear end of said bar constructed and arranged to rotate said depressor thereby disengaging said depressor from said stop when said stud engages the forward part of said shelf as said barrel extension moves into the recoil position.

4. In a firearm having a receiver, a barrel extension slidably mounted in said receiver for reciprocating movement, a breech block carrier slidably mounted in said receiver for reciprocating movement parallel to said barrel extension movement, a breech block guide surface on said carrier angularly disposed relative to the path of movement of said carrier and located rearwardly of said barrel extension, a breech block slidably mounted relative to said guide surface for reciprocable movement between two spaced positions on said guide surface, a stop secured to said breech block, a depressor pivotally secured to said carrier constructed and arranged to engage said stop, said depressor being provided to hold said breech block on said carrier in the uppermost of said two spaced positions, and means for rotating said depressor to depress said breech block to the lowermost of said two spaced positions.

5. In a firearm having a receiver, a barrel extension slidably mounted in said receiver for reciprocating movement, a breech block carrier slidably mounted in said receiver for reciprocating movement parallel to said barrel extension movement, a breech block guide surface on said carrier angularly disposed relative to the path of movement of said carrier and located rearwardly of said barrel extension, a breech block slidably mounted relative to said guide surface for reciprocal movement between two spaced positions on said guide surface, a projecting stop secured to said breech block, and locking means for engaging the under surface of said stop to hold said breech block on said carrier in the uppermost of said two spaced positions.

6. In a firearm having a receiver, a barrel extension slidably mounted in said receiver for reciprocating movement, a breech block carrier slidably mounted in said receiver for reciprocating movement parallel to said barrel extension movement, a, breech block guide surface on said carrier angularly disposed relative to the path of movement of said carrier and located rearwardly of said barrel extension, a breech block slidably mounted relative to said guide surface for reciprocal movement between two spaced positions on said guide surface, a protruding stop secured to said breech block, and a spring-biased depressor pivotally secured to said carrier and provided with a substantially upright arm with a notch therein arranged and constructed to engage the lower surface of said stop in the uppermost of said two positions.

7. In a firearm having a receiver, a barrel extension slidably mounted in said receiver for reciprocating movement, a breech block carrier slidably mounted in said receiver for reciprocating movement parallel to said barrel extension movement, a breech block guide surface on said carrier angularly disposed relative to the path of movement of said carrier and located rearwardly of said barrel extension, a breech block slidably mounted relative to said guide surface for reciprocal movement between two spaced positions on said guide surface, a protruding stop secured to said breech block, a projecting lug on said breech block carrier arranged to limit the upward movement of said breech block when the upper surface of said stop is in contact with said lug, and locking means for engaging the lower surface of said stop to hold said breech block on said carrier in the uppermost of said two spaced positions.

CLARENCE E. SIMPSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,339,661 Swartz Jan. 18, 1944 2,354,080 Webb July 18, 1944 FOREIGN PATENTS Number Country Date 607,588 Germany Jan. 5, 1935 

